Apparatus for cooking wood-pulp.



Patented Jan. 11, 1916.

L, B. DECKER.

APPARATUS FOR COOKING WOOD PULP.

APPLICATION FILED FEB. 23, I915.

LEMUEL JOHN BALL, 6F KENOGATVII, QUEBEC, CANADA.

APPARATUS FOR COOKING WOOD-PULP.

menses.

Specification of Letters Patent.

Patented Jinn. ill, ll lllfi,

Application filed Februoxy 23, 1915. Serial No. 10,095.

. To all 'w/lom iii/2.1231 concern:

Be it known that l, LEMUEL B. DECKER, n. citizen of the United States, residing at present in Kenogoiuh Province of Quebec,

a and DOlTllIllflli of Canada, have invented cor .tein new and useful Improvements in Apparatus for Cooking Wood-Pulp, of which the following is a specification 'lhis invention relates to the sulfite process ofoooking wood pulp in which chips or small pieces oi wood are placed in suitable .tligesters with the proper sulfite liquor and hosted under pressure until the cooking opera on is completed. Usually the heat and o" sure is obtained by injecting steam at toe bottom of she digest/er, the gases and liquor being conveyed from the digesters to cooling tank and thence to an acid storage milk. The trcebcd pulp usually discharged thriulgh suitable openings and discharge nines at the bottom of the digesters. This operation is'suiteble for use on specially pre-- Pill'ifil chips or small pieces of wood, but is not econcunical for use on wood in the form of sew-dust, shavings, ground wood screenings, and the like, and the object of my invention is to provide an appwutus which may lie-operated in the usual way for digest wood in, specially prepared form. and which may nlso be iu ononiicully used for digesting or cooking snn dust, shavings, ground Wood screenings and Wood. waste generally. i

In carrying out my invention, I employ one or more digcsliers of the usual kind and onerute them in the usual way for cooking wood in the form of chips and the like. The and. liquorpussing out. from the top of the digcster or digcsters muy be conveyed to cooler and thence to on acid storage tank in. toe usual way. But I also. instead of conveying the waste gases and liquor directly to the cooling tank, as heretofore sr :h. gases and liquor to puss through 1 "the iorin of pipe or pipes coir thin snot-her digostor which reu orisl oi the kind above i585? from the ordinary s and the liquor escaping puss through the heater in the wood waste digcster produce sullicient heat and pressure Within said wood waste digests! to maintain the cooking operation, sufficient hoot being developed and distributed for operating upon the waste material described. The gases and liquor puss from the heating pipes in the wood waste .digcstcr to the cooler and thence to the acid storage tank. Other features of the invention and certain details of construction will be hereinafter more fully described.

The accompanying drawings show in pen spective and dingrunlnuiticully an uppurutus for cooking wood pulp, constructed in occordnnce with my invention.

The digesters A and ill are of ordinary constructioli and may be used in the ordinary way. The digcstcr A has n detachable cover (t, to which is connected a pipe U, provided withvulves c, a, c, said pipe {i being in turn connected with a pipe line 1), ex tending to the cooling tunk E. i In like manner the digester B is provided with n lQll1(;\"-- able cover 6," connected by a pipe F provided with valves to ihepipo line D. lluch digeslcr A and B is connected at ils bottom with :1. pulp discharge pipe (l by means of u brunch pipe G having a valve 1 and .euch digestcr A and B is also (.qlllpllfill with o valved strum pipe ll which supplies the required heat and pressure for cooking purposes. The apparatus thus for described of usual construction and is opcruiod in lho usual way. I, however, employ another digcstcr l; which in general is of the usuul construction, but which contains :1 healer preferably in the form of a coil ll of lead pipe, one end of which is connected by u pipe line M and brunch pipes m, m with the pipes {l und l. The opposite end of lhe coil ll is connected by uv pipe N with the pipe line D lending to the cooler E. 'Rhe brunch pipes in, m. are equipped with valves 0, 0, and lhc pipe N is provided with a valve 1.

The digester K is provided with [ii liquor gage P having a test cock j), and at its bottom, said digester is connected by s pipe Q with ti pulp discharge pipe (i. ll indicates e valved SlZEEllll inlet pipe which may times be used. i

the usual way, and the covers a and b are bolted down. 'Steam is then admitted through the pipes ill and the pressure is raised to about los. to the square inch. The valves 0; c and f, f are then partially opened to allow air hnd gas to pass to the cooler. Then after'the air and gas have escaped the valves 0, c, f, f are fully opened while the valves 0, 0 are closed. The liquor, which is at a temperature'of about 150 C., enters the pipe line 1) and passes to the cooler and thence to the acid storage tank.

When the cooking is completed, which takes from Ste 10 hours, the valves 7 may be opened, and the pulplmay pass out through the pipes G. The apparatus may be used in this way to the exclusion of the digester K, but when it is desired to cook waste wood material otthe kin'd before mentioned the valves f are closed, and the valves n, 0'

and n are opened. Before doing this, however, the waste wood is placed in the digester- K and acid liquor is pumped into the digester through the valved pipe S. When the liquor has risen to the proper level, as will be indicated by the gage P the valves 0, 0' are opened as before described, or only one valve, .say the valre 0, may be opened. in

order thatgas anti liquor of the highest possible temperature may be obtained. In any event the gas a d liquor entering the pipe line M pass to and through the coil L and supply and maintain the necessary temperature for cooking purposes, which latter usually takes from 24: to 30 hours. The gas and liquor after passing through the coil L continue on through the pipe N and thence pass to the acid storage tank. The digester K is connected by a pipe T provided with valves t, t with the pipe line Das shown.

It may sometimes be desirable to., assist the cooking operatioh by admitting a relatively small quantity of steam through the pipe 11, in which case the air and gas as well as the liquor may pass out to the pipe line D when the valves t 6" are opened, and these valves may also be left open when required to permit the passage of air, gas or liquor from the digester K to said pipe line.

It will be seen that in my apparatus I dispense with the use of steam in the wood:

waste digester, and thus effect a large saving'in the cost of manufacture, the heat (say It is not possible to economically cook sawdust, ground wood sereemngs, small coarse slivers and the like in the ordinary digesters, such as A and B owing to" the fact that in such digesters the heat is not sufiiciently distributed and as such digesters usually contain strainers beneath the covers which become clogged. In the digester K the coil L thoroughl distributes the heat and a complete cooking of the material is efieoted.

Experience has demonstrated that by my apparatus small chips or small pieces of wood, saw-dust, ground wood screenings and the like can be cooked into sulfite pulp at a saving of four to ten dollars per ton.

I claim as my invention p 1. An apparatus for cooking wood pulp, comprising a main digester, an acid cooler connected therewith, means for admitting steam to. the digester, another or wood waste digester provided with a heater within it connected with the main digester and with the cooler, and means for directing the flow of gas and liquor from the main digester either directly to the cooler orthrough the heater in the wood waste digester to the cooler.

2. An apparatus for cooking wood pulp, comprising a main digester, an acid cooler, means for admitting steam to said digester, a wood waste digester, a heating coil arranged therein and connected with the main digester and withthe cooler, a connection between the interior of the Wood waste. digester and the cooler, and means-for admitting steam to the last named digester. y

.3. An apparatus for cooking wood pulp,

comprising a main digester, an acid cooler,

pipe connections between the cooler and said digester,'means for admitting steam to themain digester, a wood waste digester, a heating coil within said last named digester, apipe line'connecting said coil with the pipe line connecting the main digester with the cooler, another pipe connecting the coil with said pipe line leadingtothe cooler, and

valves in said pipes and pipe lines for directing the acid liqu0r,and gas from the main digester directly to the cooler or to the cooler through said coil .for the purpose specified.

4.. An apparatus for cooking wood pulp,

comprising a main digester, an acid cooler, In testimony whereof, I have hereunto means for admitting steam Itlo said digester, subscribed my name.

a Wood Waste digester, a. eatin coil ar- T ranged therein for distributing the heat LEMLEL DECKER therethrough, connections between the main Witnesses: Y digester and the heating coil, and a connee- WM. CROWLEY, tion betweenthe heating coil and the coqier. W. J. MONAHAN. 

